2. Pat the scallops dry with paper towels and season them generously with salt and pepper. Toss the scallops in the flour and shake them to remove any excess flour. Heat 2 tablespoons of olive oil in a large (12-inch) sauté pan. When the oil is very hot, add half the scallops and sauté on one side without moving until they are browned, about 3 minutes. Turn the scallops and cook for about 2 minutes more so the scallops are still a little raw in the center. Transfer the scallops to a heatproof platter and keep them warm in the oven. Repeat with the remaining scallops and add them to the platter in the oven.

3. Melt the butter in the pan and add the shallots. Cook over medium heat for 2 minutes. Add the mushrooms and cook for 4 to 5 minutes, turning often, until browned and tender. Add the wine and scrape up the brown bits with a wooden spoon. Cook for 2 minutes to reduce the wine.

4. Add the spinach to the pan in handfuls, so some of it wilts before adding more. Toss the spinach with the sauce to help it wilt. When all of the spinach has been wilted, add the spinach mixture to the scallops in the oven. Sprinkle with the Parmesan cheese and bake for 3 minutes, until the scallops are just cooked. Sprinkle with pepper and serve hot with wedges of lemon.